Improvement in girders for bridges



A J. EVANS;

Girders forBridges.

Patented Nv.18,1873.r

NITED STATES i JAMES W. EVANS, OF NEW YORK, N. Y.

IMPROVEMENT IN GIRDERS FOR BRIDGES.-

Specification forming part of Letters Patent No. 144,75 1, dated November 18, 1873; application tiled April 9, 1823.

To all whom it may cqncem:

Beit known that I, JAMES W. EVANS, of the city, county, and State of New York, have invented an Improved Girder'for Bridges, Snc., of which the following is a specification:

Figure l is a side elevation, partly in section, of my improved girder for bridges. Fig.`

2 is a top view of the same; Fig. 3, a sectional perspective view thereof Fig. 4, a detail transverse section on the line c c, Fig. 2.

Similar letters of reference indicate corresponding parts in all the gures.

The object of this invention is to improve the construction of the longitudinal girders of bridges, railroad-crossings, &c., with a view toward increasing their strength, lightness, and cheapness, and for providing free expansion and contraction under the influence of heat and cold. The invention is particularly applicable for use on elevated railroads over streets in cities and towns; and consists in making the lower chord of the girder of three concentric parts, of which the outer is tubular, the next inner also tubular,

'and the innermost of wire-rope.

site stillness and main support to the girder.

My invention also consists in casting on the outer shell upwardly-projecting lips, between which the sleepers of the rails, in case the chord is to be used as a support for a railwaytrack, are embedded, they beingV thereby properly sustained on the top of the outer shell, and prevented from lateral dis-A placement by the aforementioned lips.

In the accompanying drawing, the letter A vrepresents the lower chord of my improved girder, supported on posts or abutments B B at its ends, and connected, by upright braces G C, with an arch, D, the braces C connecting, at the lower ends, with transverse beams E, that constitutethe suspensionsup ports of the brace A.

rlhere may be two or more girders on each bridge or crossing; and there may also be a series of oblique braces, F, as shown in Fig. 2, that extend diagonally underthe gird of suitable length; the sections of the outer` tube, d, being substantially of the .same length, but so placed, with respect to the sections of b, that the joints of the inner and outer tubes will be broken, as shown at the sectional part of Fig. l, and also indicated in Fig. 3. The outer shell or tube, d, has upwardlyprojecting lips ff, which serve as side supports for the sleepers g of the railroad-rails h.

When the bridge is not to be used as a support for a railroad, these lips f may be dispensed with, although ,they may be applied, in that case, or'holding longitudinal beams that support the bridgeplanking.

When several spans of a bridge or crossing of this construction are arranged inline, the adjoining posts B B of the two spans have a space left between them, which is bridged by a connectingplate, G. This plate G has downward-projecting flanges i, that are notched to embrace the nuts e, and thereby prevent said nuts from turning.

Whenever it is desired to turn these-nuts it is rst necessary to raise the connecting-plate G off its supports, and thereby to liberate the nuts.

Between every pair of sections of the outer shell, d, is placed a washer, j, which I prefer to make of corrugated metal; or whichmay, if desired, be made of elastic material, such as rubber, or otherwise. The elasticity of this washer allows the girder to expand and con` tract lengthwise, and still serves to keep the 2. The shell d, provided with projecting joints tight and properly closed. lips ff for holding the sleepers g, substantially I claim as my invention, and desire to seas described.

eure by Letters Patent- J AMES W. EVANS.

l. The lower chord A, constructed of an Vitnesses:

outer tubular shell, d, inner tube b, Wire-rope DAVID L. MISELL,

core a, substantially es described. M. RYAN. 

